* {
    margin: 0;
    padding: 0;
    color: #000000;
}
html {
    font-size: 18px;
}
.learn {
    padding: 0 30px;
}
.learn h1 {
    font-size: 30px; 
    text-align: center;
    line-height: 2;
}
.learn h2 {
    font-size: 26px;
    margin-left: .5rem;
    line-height: 2;
}
.learn h3 {
    font-size: 22px;
    margin-left: 1rem;
    line-height: 2;
}
.learn p {
    margin-left: 2rem;
    text-indent: 2em;
    font-size: 18px;
    line-height: 2;
}
.learn ul {
    font-size: 18px;
    margin-left: 2rem;
    text-indent: 2em;
}
.learn pre {
    font-size: 18px;
}